Molded slider for slide fasteners



Feb. 24, 1942. N. J. POUX MOLDED SLIDER FOR SLIDE FASTENERS Filed June30, 1938 By ATTORNEYS.

one in that it comprises Patented Feb. 24, 1942 UNITED I STATES PATENTOFFICE Noel J. Poux, Meadville, Pa.,

Inc., a corporation of assignor to Talon, Pennsylvania Application June30, 1938, Serial No. 216,729

3 Claims.

My invention relates to molded sliders ior slide fasteners.

In the manufacture of sliders from plastic material such as celluloseacetate or cellulose nitrate, the method usually employed is to moldslider bodies in one piece. The shape of a slider from a structuralstandpoint is a rather unique top and bottom wings which must be heldtogether in accurate fixed spaced relation but which can be connectedtogether only in the narrow central portion at one end of the wings.

It is therefore highly important to make this, neck connection as strongas possible and the many patents in the art of slide fasteners directedto the making of strong necks in metal sliders will attest to this fact.In molded sliders of plastic material the strength of this neck is notas great as the strength of a metal neck in a slider of correspondingsize and it-becomes all the more important to maintain uniformity andthe maximum possible strength. The thickness of the material in the neckhas been made substantially greater than the thickness of the wingmaterial and it has been found in experience that while some of thesliders have suflicient strength there will be considerable variation.1- have discovered that the strength of the material at the surface ofthese molded sliders is greater than in the interior and my inventionutilizes that fact in producing molded sliders in which the neck willhave more uniform thickness and greater strength.

It has also been observed in molded sliders that there will be adepression in the surface of the slider adjacent the neck portion whenthe neck is molded. This is believed to be due to the shrinkage of therelatively large mass of material in cooling adjacent the neck portion.

My invention also overcomes this difliculty.

In the accompanying drawing I have shown well known and are explained innumerous prior patents. A slider generally designated 1 is moved overthe fastener elements in opening or closing the fastener by means of apull tab 8.

for purposes of illustration one embodiment which my invention mayassume in practice. In the drawing: Fig. 1 shows a portion of a slidefastener equipped with my improved slider;

Fig. 2 shows a rear end view of the slider; Fig. 3 shows a verticallongitudinal cross-section; and

Fig. 4 shows a horizontal central crosssection. The slide fastener onwhich my improved slider is mounted comprises a pair of fabric tapes 5having flxed on their adjacent edges rows of fastener elements 6. Theconstruction and operation of the fastener elements of this type are Theslider body is a one-piece integral molded structure comprising a topwing 8 and a bottom wing I 0, an integral neck connection H, and a lugor loop H! on the top 'wing aflording means for convenient attachment ofthe pull tab. At least one of the wings in the present instance has sideflanges l3 bearing against the ends of the elements and which guide themthrough the interior channel of the slider. As seen from the rear end ofthe slider in Fig. 2 the over-all width of the neck is substantiallygreater than the thickness of the wing material. In the practiceheretofore of molding the neck as a solid element, there is a mass ofmaterial of substantially greater thickness than the wing material anddue to the variable characteristics of the material used, the internalstructure of the material in this wide portion of the neck varies andaccordingly the strength of the slider is difiicult to control.According to my invention a recess l4 extends from the rear end of theneck well toward its pointed end so that the side walls H of the neckwill have a thickness approximately equal to or less than the thicknessof the top wing material. The V-shaped neck itself extends well into thewing and its pointed end It is located between the side flanges l3. Itis not sufl'lcient for my purpose to have only'a shallow recess, (whichhas been an incidental result in certain methods of molding slidersheretofore employed), but it is necessary that the recess l4 extend asubstantial distance into the neck. Preferably it is rectangular incross-section at the entrance end, the height of the recess beingsubstantially as great as the distance between the wings. The walls I!of the recess are preferably run parallel up to the tapered portion ofthe neck and then the walls converge to a point I8 so that the resultingrecess has a depth substantially greater than half the total length ofthe neck. Because it is usual to form the neck in a portion of theslider which extends rearwardly beyond the ends of the flanges l3, it isconvenient to have this recess extend to a point substantially in linewith the ends of the flanges. While the benefits of my invention may besecured at least to some extent with other forms point of the V so thatthe maximum thickness oi any section of the neck is substantially lessthan the over-all width. This results in much greater uniformity ofstrength and the surface area is very greatly increased. Accordingly, myinvention utilizes the material to the greatest possible advantage.

While I have shown and described in this apslide fasteners comprisingtop and bottom wings,

an integral wing connecting neck extending from one end well into thewings, said neck having a molded-in recess of a length at least half asgreat as the length of the neck.

2. A non-metallic molded plastic slider for slide fasteners of the classdescribed comprisingtop and bottom wings, an integral connecting neckV-shaped in cross-section extending from the rear end of the slider wellinto the wings, said neck being hollow with molded surfaces and havingwalls of substantially uniform thickness apggoximately the same as thethickness of the w s.

3. A one-piece integral non-metallic molded plastic slider for slidefasteners, comprising top and bottom wings, an integral neck connectinsthe wings at one end for holding them in iixed spaced parallel relation,said neck being V- shaped in horizontal cross-section and having amolded-in" recess extending lengthwise into the neck, the walls of therecess in horizontal crosssection being of substantially uniformthickness and substantially parallel at the entrance end of the recessand converging toward the end of the recess between the converging sidesof the neck, the high ratio of molded skin area to volume of material insaid neck producing high strength and rigidity therein.

. NOEL J. POUX.

